Lanthanide-based perovskite oxides have been theoretical predicted as the most prospective cathode catalysts for lithium-oxygen (Li-O₂) batteries owing to their superior chemical stability and composition adjustability. However, their inherent activity still needs further improvement and the intrinsic catalytic mechanisms are poorly understood during oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) process. Herein, a facile nonstoichiometric strategy is implemented to fabricate perovskite LaMnO_3-δ with abundant A-site cationic defects for the first time. The Li-O₂ cell with the as-prepared La_0.7MnO_3-δ (L_0.7MO) dual-function electrocatalyst delivers ultrahigh discharge capacity (29,286 mAh g⁻¹), extremely low overpotential (0.38 V) and superior long-term cycling durability (375 cycles at 300 mA g⁻¹). The well-defined La defects make crucial contribution in modulating the local unsaturated coordination state of active Mn atoms and thus regulating the electronic structure of L_0.7MO, which prominently enhances the oxygen redox kinetics in Li-O₂ battery. Specifically, experimental results and density function theory (DFT) calculations demonstrate that La vacancies conspicuously increase the covalency of Mn-O bonds, thus optimizing the e_g electron filling states of the active Mn cation and enhancing the overlapping state of Mn 3d-O 2p hybridization, which promotes lattice oxygen participated redox reaction and accelerates the electron transport between the Mn cations and oxygen adsorbates (e.g., O₂²⁻, O²⁻). In addition, the abundant crystal defects endow the surface with strong adsorption capability for LiO₂ intermediate and hence fundamentally regulate the formation and decomposition mechanism of Li₂O₂.

镧系钙钛矿氧化物由于其优异的化学稳定性和成分可调性，已被理论预测为最有前景的锂氧（Li-O ₂）电池阴极催化剂。然而，它们的内在活性仍需要进一步提高，并且在氧还原反应（ORR）和析氧反应（OER）过程中的内在催化机制知之甚少。在此，首次实施了一种简便的非化学计量策略来制造具有丰富 A 位阳离子缺陷的钙钛矿 LaMnO _3-δ。锂-O ₂与所述制得的La细胞_0.7的MnO _3-δ（L _0.7MO) 双功能电催化剂提供超高放电容量 (29,286 mAh  g ^-1 )、极低过电位 (0.38 V) 和卓越的长期循环耐久性（300 mA g ^{-1 下}循环 375 次 ）。明确定义的 La 缺陷在调节活性 Mn 原子的局部不饱和配位态方面做出了重要贡献，从而调节了 L _0.7 MO的电子结构，从而显着增强了 Li-O ₂电池中的氧氧化还原动力学。具体而言，实验结果和密度函数理论（DFT）计算表明空缺的La显着增加的锰-O键的共价性，从而优化电子_克Mn 阳离子的电子填充状态和增强 Mn 3d-O 2p 杂化的重叠状态，促进晶格氧参与氧化还原反应并加速 Mn 阳离子和氧吸附物（例如，O ₂ ^2-，O ^{2 -} )。此外，丰富的晶体缺陷使表面对LiO ₂中间体具有很强的吸附能力，从而从根本上调节了Li ₂ O ₂的形成和分解机制。